EP0425060A2 - Verfahren zum Spritzgiessen und Vorrichtung dafür - Google Patents

Verfahren zum Spritzgiessen und Vorrichtung dafür Download PDF

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Publication number
EP0425060A2
EP0425060A2 EP90250266A EP90250266A EP0425060A2 EP 0425060 A2 EP0425060 A2 EP 0425060A2 EP 90250266 A EP90250266 A EP 90250266A EP 90250266 A EP90250266 A EP 90250266A EP 0425060 A2 EP0425060 A2 EP 0425060A2
Authority
EP
European Patent Office
Prior art keywords
resin
injection
mold
molten resin
mold cavity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP90250266A
Other languages
English (en)
French (fr)
Other versions
EP0425060B1 (de
EP0425060A3 (en
Inventor
Masayoshi C/O Nagoya Techn. Inst. Kasai
Hideo C/O Nagoya Techn. Inst. Kuroda
Yukio C/O Nagoya Techn. Inst. Tamura
Yoshio C/O Nagoya Machinery Works Shikase
Kouji C/O Nagoya Machinery Works Kubota
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Heavy Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP1278473A external-priority patent/JPH03140222A/ja
Priority claimed from JP1278474A external-priority patent/JP2734477B2/ja
Priority claimed from JP1278475A external-priority patent/JP2647515B2/ja
Application filed by Mitsubishi Heavy Industries Ltd filed Critical Mitsubishi Heavy Industries Ltd
Publication of EP0425060A2 publication Critical patent/EP0425060A2/de
Publication of EP0425060A3 publication Critical patent/EP0425060A3/en
Application granted granted Critical
Publication of EP0425060B1 publication Critical patent/EP0425060B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/76—Measuring, controlling or regulating
    • B29C45/78—Measuring, controlling or regulating of temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/20—Injection nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B29C45/561—Injection-compression moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/70—Means for plasticising or homogenising the moulding material or forcing it into the mould, combined with mould opening, closing or clamping devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/72—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/76—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/76—Measuring, controlling or regulating
    • B29C45/77—Measuring, controlling or regulating of velocity or pressure of moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C2045/0098—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor shearing of the moulding material, e.g. for obtaining molecular orientation or reducing the viscosity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
    • B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
    • B29C45/561—Injection-compression moulding
    • B29C2045/5615—Compression stroke, e.g. length thereof

Definitions

  • the present invention relates to a process of low clamping pressure injection molding for producing injection-molded plastic products with high dimensional accuracy under a lower molding pressure.
  • a compensation of the size reduction incidental to the cooling of the molded article should be incorporated.
  • an imposition of an effective pressure onto the molten resin in the mold cavity becomes hindered when the gate is clogged or sealed, whereby the cavity internal pressure will then be settled in the unbalanced state as mentioned above and the molded resin will be cured as such upon cooling.
  • the unbalance of the internal pressure is frozen in the molded article as an internal stress. This may cause defective dimensional stability and occurrence of distortion and sink mark. A waste of useless energy due to occurrence of pressure drop etc. may also be taken into account of.
  • Metal molds made of ZAS (a zinc alloy) enployed conventionally for molds for limited production of moldings are apt to be subjected to deformation by internal pressure, formation of flashes in the molded articles due to opening or spacing between the parting faces, damages of the mold and decreased working life, though they are available at a price about half as high as that of steel mold (made of, for example, S55C or so on). If such deformation of the mold would be able to be limited to an extent comparable to that expected for carbon steel mold, a mass production of moldings using ZAS mold could be realized.
  • Table 1 Young's Modulus and Max. permissible Internal Pressure for Mold Materials Material of Mold Young's Modulus (MPs) Max. permis. Int. Press. (MPa) Steel 21 100 Zn-alloy (ZAS) 4.5 20
  • the present invention it is contemplated to provide a process and apparatus for effecting injection molding of plastic resin products under a low clamping pressure in which the molding can be realized with a maximum internal pressure below 20 MPa or with an molding pressure of 1/5 of that encountered normally in steel molds, as corresponding to the ratio of Young's modulus of ZAS to that of steel, in order to realize rediction of the investment cost for mold.
  • one aspect of the present invention resides in a process for effecting injection molding of plastic resin products on an injection molding apparatus including a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection means with an injection nozzle permissible of adjusting the nozzle flow path section, comprising a first molding step of injecting a molten resin into the mold cavity which has been preset by the slidable mold element so as to include a post-compression margin to be compressed afterwards in a second molding step, to effect the injection under a reduced molding pressure, while causing generation of a shearing energy in the injected flow of the molten resin by throttling the nozzle, to effect a temperature elevation and, thus, a viscosity reduction of the molten resin, until the mold cavity has been filled up, and a second molding step of compressing the resin so charged in the mold cavity by operating the slidable mold element to compress the charged resin to compensate said post-
  • Another aspect of the present invention resides in a process for effecting injection molding of plastic resin products on an injection molding apparatus including a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection means with an injection nozzle, comprising a first molding step of injecting a molten resin into the mold cavity which has been preset by the slidable mold element so as to include a post-compression margin to be compressed afterwards in a second molding step, to effect the injection under a reduced molding pressure, while causing generation of a shearing energy in the injected flow of the molten resin by incorporating a means for throttling the flow path of the molten resin and/or a means for heating the molten resin before being injected into the mold cavity to effect a temperature elevation and, thus, a viscosity reduction of the molten resin, until the mold cavity has been filled up, and a second molding step of compressing the resin so charged in the mold cavity
  • a further aspect of the present invention resides in a process for effecting injection molding of plastic resin products on an injection molding apparatus including a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection means with an injection nozzle permissible of adjusting the nozzle flow path section, comprising a first molding step of injecting a molten resin into the mold cavity which has been preset by the slidable mold element so as to include a post-compression margin to be compressed afterwards in a second molding step, to effect the injection under a reduced molding pressure, while causing generation of a shearing energy in the injected flow of the molten resin by incorpora­ting, together with a throttling of the injection nozzle, a means for throttling the flow path of the molten resin and/or a means for heating the molten resin before being injected into the mold cavity to effect a temperature elevation and, thus, a viscosity reduction of the
  • a still further aspect of the present invention resides in an apparatus for effecting injection molding of a plastic resin
  • a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection means having an injection nozzle permissible of adjusting the nozzle flow path section, comprising a means for settling the pertinent position of the slidable mold element relative to the fixed mold element to be determined by taking into account of the amount of volume reduction of the molded resin product due to the cooling thereof after the injection molding and a means for adjusting the flow rate and the molding pressure upon each injection cycle in linkage with a means for varying the flow path section of the nozzle for the molten resin, for realizing reduction in the viscosity of the molten resin and, thus, in the pressure drop of the flowing resin within the mold cavity.
  • a further aspect of the present invention resides in an apparatus for effecting injection molding of a plastic resin including a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection means having an injection nozzle permissible of adjusting the nozzle flow path section, comprising a means for settling the pertinent position of the slidable mold element relative to the fixed mold element to be determined by taking into account of the amount of volume reduction of the molded resin product due to the cooling thereof after the injection molding and a means for elevating the temperature of the plasticized resin including a means for throttling the flow path of the molten resin to the mold cavity and/or a means for settling a higher temperature of the heater in the screw plasticing region, for increasing the screw back pressure or for increasing the rate of revolution of the screw, for realizing reduction in the viscosity of the molten resin and, thus, in the pressure drop of the flowing resin within the mold cavity.
  • a still further aspect of the present invention resides in an apparatus for effecting injection molding of a plastic resin including a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection means having an injection nozzle permissible of adjusting the nozzle flow path section, comprising a means for settling the pertinent position of the slidable mold element relative to the fixed mold element to be determined by taking into account of the amount of volume reduction of the molded resin product due to the cooling thereof after the injection molding; a means for elevating the temperature of the plasticized resin including a means for throttling the flow path of the molten resin to the mold cavity and/or a means for settling a higher temperature of the heater in the screw plasticing region, for increasing the screw back pressure or for increasing the rate of revolution of the screw; and a means for adjusting the flow rate and the molding pressure upon each injection cycle in linkage with a means for varying the flow path section of the nozzle for the molten
  • the injection of the molten resin into the mold cavity can be realized in the process according to the present invention under a reduced molding pressure by employing a two step molding in which the molten resin is injected, in the first molding step, into the mold cavity settled by operating the slidable mold element so as to include a post-compression margin to be compensated by compression in the second molding step, since thereby the pressure drop of the molten resin flowing within the mold cavity is reduced.
  • the temperature of the molten resin is elevated by the shearing heat generated, causing thus reduction of the viscosity of the molten resin, and it is made possible to inject molten resin, of which viscosity has been reduced as above and eventually further with assist by a means for elevating the temperature of the molten resin, into the mold cavity with the pressure drop within the mold cavity, and thus, the molding pressure being thus additionally reduced.
  • a screw 1 is arranged extending slidably within a closed space 2a defined by a cylinder 2, an end cap 3 and a throttled nozzle 4.
  • the raw resin to be molded is supplied into a hopper 5 from which it is fed to the cylinder 2 and is plasticized and melted by the action of the screw 1 rotated by a hydraulic motor 6 together with heating by a not shown heater.
  • the thus melted resin is sent forward by the screw and is stored at the cylinder end as molten resin stock 7.
  • the axis 6a of the hydraulic motor is held in a spline engagement with an injection ram 8 so as to rotate integrally with it, while permitting free axial slide with each other.
  • 9 is a position sensor for the screw 1.
  • the screw 1 is so actuated that the hydraulic fluid is supplied from a hydraulic fluid source 12 upon a command from a central control unit 11, to the injection cylinder 15 via an electromagnetic control valve 13 and a flow rate control valve 14 to cause the molten resin stock 7 be injected into the mold cavity.
  • the particulars of the throttled nozzle 4 are shown in Fig. 2 in an enlarged axial section.
  • the nozzle 20 having inserted in the central flow path a needle pin 21 is firmly secured on the front end of a valve body 22 commnicating via the end cap 3 to the cylinder 2.
  • the needle pin 21 is connected with a lever 23 which is pivotingly connected to a connection link 24 through a cut-off 21a provided on the needle pin 21, whereby it is driven by a hydraulic driving means 25 shown in Fig. 1.
  • the hydraulic driving means 25 is mounted fixedly on the cylinder 2 via a bracket 26.
  • a position sensor 27 detects the position of stroke of the piston 24 and, thus, the position of the fowarding end or the retoceding end of the needle pin 21.
  • the molten resin flows through a plurality of canals 22a (Fig. 2) distributed over the circumference of the valve body 22 snd a flow path 20b and discharges out of the nozzle hole 20a.
  • the valve body 22 is mounted on the end cap 3 by screw bolts 28 and the nozzle 20 is screwed in the valve body 22.
  • the needle pin 21 is inserted in the valve body 22 freely slidably with the front end thereof being held so as to left a gap d1 between it and the nozzle hole inner face and the rear end thereof being fixed to the lever 23 as mentioned above.
  • a servo valve 29 serves for servo controlling the gap d1 by detecting the position of stroke of the hydraulic driving means 25 to producing thereby detection signals which are sent to the central controller 11 in which the signals are converted into actuation signals for sliding the needle pin 21 to settle the gap at d1.
  • the actuation signals from the detected signals are compared with the signals for a preset standard for d0 and the difference thereof, namely, incremental or decremental signals are supplied to the servo valve 29.
  • the gap d1 is closed by forwarding the needle pin 21, in order to prevent flowing out of the molten resin of low viscosity after it has been plasticized and melted.
  • the needle pin is retrogressed so as to reach full opening of the gap d1.
  • a slidable plate 31 (Fig. 1) having fixed thereto a slidable mold element 32 is arranged so as to allow its slide by a clamping cylinder 33.
  • the slidable mold element 32 engages with a fixed mold element 35 mounted fixedly on an immovable plate 34 and defines together a mold cavity 36.
  • the mold elements are brought into engagement in the first molding step so as to thereby effect a primary clamping with a preset cavity space including a post-compression margin ⁇ which will be compensated by compression in the second molding step.
  • a spacer member 37 having a form of wedge is interposed between the slidable mold element 32 and the fixed mold element 35 under control by a driving means 38.
  • a position sensor 39 is provided for detecting the stroke position of the wedge spacer 37.
  • the wedge angle ⁇ of the spacer 37 is so selected that a minute adjustment of the compression margin ⁇ can be attained by the adjustment of lapping length l of the spacer with the mold elements.
  • several wedge spacers 37 are disposed between the two mold elements (35, 32) under a uniform distribution over the circumference of the mold elements.
  • an electromagnetic change-over valve 40 and an electromagnetic relief valve are provided, which serve for controlling the rate of supply of the hydraulic liquid from the hydraulic liquid source 12 under control by a control signal from the controller 11.
  • a highly fluidized molten resin in the resin stock 7 is now injected into the cavity 36 preset with the post-­compression margin ⁇ from the nozzle 4 at a high injection velocity to fill the cavity.
  • the controller 11 gives out a signal to the electromagnetic change-over valve 40 and to the electromagnetic relief valve 41, after the injection has been finished, to cause the primary clamping pressure to be reduced.
  • the wedge spacers 37 are retroceded before the gap d1 of the throttled nozzle 4 is closed by a signal supplied to the servo valve 29.
  • the slidable mold element 32 is operated to compress the cavity 36 at a predetermined secondary clamping pressure for a predetermined period of time by each command signal supplied from the controller 11 to the electromagnetic change-over valve 40 and to the electromagnetic relief valve 41.
  • the molded article is taken out after the mold has been cooled and the molded article has been sufficiently cured, by opening the mold by operating the slidable mold element 32.
  • Apparatus An injection molding machine of 900/­220 MPa Mold : For molding a 200 ⁇ circular disc (See Fig. 6) with a gate size (disc gate) of 0.3, 0.7 and 1.0 mm and a wall thick­ness of the molded disc of 1.3 mm
  • Resin Tafrex 210-W (an ABS resin) of the firm Mitsubishi Monsanto Chemical Co. Molding : Mold temperature of 50, 100 and 130 °C Resin temperature of 210, 250 and 290 °C Injection rate at 50, 100, 200 and 500 cm3/sec
  • molding pressure it is defined as the pressure at cavity entrance upon completion of the injection (at the occasion at which the cavity terminal end pressure reaches zero).
  • the molding pressure can be reduced from 50 MPa to 32 MPa (from point 1 to point 2 on the diagram of Fig. 7) (effect of gate throttling).
  • the molding pressure can be reduced from 32 MPa to 22 MPa (from point 2 to point 3 on the diagram) (effect of wall thickness increase).
  • the injection rate from 100 cm3/sec to 300 cm3/sec, the molding pressure can be reduced from 22 MPa to 17 MPa (from point 3 to point 4 on the diagram) (effect of injection rate increase).
  • a final molding pressure lower than 20 MPa is attainable.
  • the items 1 and 3 correspond both to a resin temperature elevation effect due to the heat generation from shearing energy upon passing the molten resin through the gate. While the above experiments were carried out by throttling the gate of the mold, it is evident that the same effects can be attained by throttling the nozzle. Here also, it is possible to reduce the molding pressure from 50 MPa to 20 MPa.
  • a final specific volume of 1.0 cm3/g can be attained even by employing a low molding pressure of, for example, 10 MPa, by pressing the injection molded heat resistant ABS resin at a thermal deformation temperature of 110°C , since an effective pressure can be imposed onto the molded resin at temperatures up to a temperature near the thermal deformation point.
  • a high density molded article having a density even higher than that of the injection molded article can be obtained.
  • Figs. 9 and 10 illustrate the second embodiment of the process according to the present invention.
  • an oxidative deteriolation preventing means may be incorporated in the injection molding apparatus as shown in Fig. 1, which is illustrated by its fundamental construction in Fig. 9, wherein the same elements as those shown in Figs. 1 and 2 are denoted with the same numeral symbols.
  • Fig. 10 is an enlarged sectional view of the second embodiment of the present invention of Fig. 9.
  • the shaft sealing portion 51 of the screw 1 has the same diameter with the screw flight 52.
  • a packing 53 is fitted to the cylinder 2 by a packing gland 54 through not shown bolts.
  • O-rings 55 and 56 are arranged.
  • a nitrogen gas bomb 58 is employed with a stop valve 59 and a flow rate control valve 60.
  • a nitrogen gas conduit 61 is guided through the hopper cylinder 62 and is connected to a nitrogengas nozzle 63.
  • the nozzle 63 is disposed at a position distant from the screw 1 by a gap d .
  • a stop valve 69 serves to shut up the line upon exchange of the gas bomb 58.
  • the hopper portion 64 is filled with nitrogen gas by flowing nitrogen gas at a constant rate operated by the command signal from the central controller 11, whereby oxidative deterioration of the molten resin is prevented.
  • the cavity entrance pressure can considerably be reduced, whereby a load-time relationship as shown in Fig. 5 was able to attain. Comparing the pressure drop ⁇ p2 inside the cavity in this embidiment with ⁇ p1 of the conventional process, it is seen that a considerable decrease in the pressure drop is achieved by the present invention due to the reduction in the viscosity of the molten resin. In addition, the unbalance of the cavity entrance pressure with the cavity terminal end pressure is also eliminated almost completely.
  • a large reduction of the molding pressure for example, from 50 MPa to 17 MPa, namely below 20 MPa, by incorporating a mold cavity thickness increasing effect by injecting, in the first step, the molten resin into the mold cavity held at a preset cavity space including the post-­compression margin to be compensated afterwards in the second step and a resin temperature increasing effect due to a heat generation by shearing energy caused by throttling of the injection nozzle or of the resin flow path, due to employment of a high temperature plasicizing and due to employment of a high-speed injection.
  • a molded article having higher dimensional stability can be obtained even under a lower compressive pressure of, for example, 10 MPa.
  • a considerably lower clamping force as compared with the conventional practice can be employed.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
EP90250266A 1989-10-27 1990-10-18 Verfahren zum Spritzgiessen und Vorrichtung dafür Expired - Lifetime EP0425060B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP1278473A JPH03140222A (ja) 1989-10-27 1989-10-27 射出成形方法及び装置
JP278473/89 1989-10-27
JP1278474A JP2734477B2 (ja) 1989-10-27 1989-10-27 射出成形方法及び装置
JP278475/89 1989-10-27
JP278474/89 1989-10-27
JP1278475A JP2647515B2 (ja) 1989-10-27 1989-10-27 射出成形方法

Publications (3)

Publication Number Publication Date
EP0425060A2 true EP0425060A2 (de) 1991-05-02
EP0425060A3 EP0425060A3 (en) 1992-01-29
EP0425060B1 EP0425060B1 (de) 1995-08-23

Family

ID=27336561

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90250266A Expired - Lifetime EP0425060B1 (de) 1989-10-27 1990-10-18 Verfahren zum Spritzgiessen und Vorrichtung dafür

Country Status (3)

Country Link
EP (1) EP0425060B1 (de)
KR (1) KR920009940B1 (de)
DE (1) DE69021824T2 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1021421C2 (nl) * 2002-09-10 2004-03-11 Fountain Patents B V Inrichting en werkwijze voor het vervaardigen van producten uit een warm plastische massa.
NL1027076C2 (nl) * 2004-09-20 2006-03-22 Ecim Technologies Bv Inrichting en werkwijze voor het vervaardigen van kunststof producten.
NL1034658C2 (nl) * 2007-11-08 2009-05-11 Green Invest Bvba Spuitgietwerkwijze en spuitgietinrichting.
WO2011054080A1 (en) 2009-11-03 2011-05-12 Husky Injection Molding Systems Ltd. A method and system for operating an injection molding machine
FR2969526A1 (fr) * 2010-12-22 2012-06-29 Visteon Global Tech Inc Procede et dispositif pour le controle de l'ouverture partielle d'un moule d'injection de matiere plastique
CN105114367A (zh) * 2015-09-02 2015-12-02 上海核工程研究设计院 一种用于核电站抽真空系统的具有可调式喷嘴的真空喷射器
EP3131729B1 (de) 2014-04-15 2018-11-28 Plastisud Tandemwerkzeug zum herstellen spritzgegossener kunststoffteile

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EP2421688A4 (de) 2009-04-24 2013-09-25 Husky Injection Molding Hohlraumeinsatz mit verformbarem teil für ein formsystem

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US7891970B2 (en) 2002-09-10 2011-02-22 Ecim Technologies B.V. Apparatus and method for manufacturing products from a thermoplastic mass
NL1021421C2 (nl) * 2002-09-10 2004-03-11 Fountain Patents B V Inrichting en werkwijze voor het vervaardigen van producten uit een warm plastische massa.
US8360769B2 (en) 2002-09-10 2013-01-29 Ecim Technologies B.V. Apparatus for manufacturing products from a thermoplastic mass
WO2004024416A1 (en) * 2002-09-10 2004-03-25 Fountain Patents B.V. Apparatus and method for manufacturing products from a thermoplastic mass
EP2033761A1 (de) * 2002-09-10 2009-03-11 ECIM Technologies B.V. Vorrichtung und Verfahren zum Herstellen von Gegenständen aus thermoplastischer Masse
NL1027076C2 (nl) * 2004-09-20 2006-03-22 Ecim Technologies Bv Inrichting en werkwijze voor het vervaardigen van kunststof producten.
WO2006033571A1 (en) * 2004-09-20 2006-03-30 Ecim Technologies B.V. Apparatus and method for manufacturing plastic products
NL1034658C2 (nl) * 2007-11-08 2009-05-11 Green Invest Bvba Spuitgietwerkwijze en spuitgietinrichting.
WO2009061200A2 (en) * 2007-11-08 2009-05-14 Green Investments Bvba Injection molding method and injection molding apparatus
WO2009061200A3 (en) * 2007-11-08 2009-06-25 Green Invest Bvba Injection molding method and injection molding apparatus
WO2011054080A1 (en) 2009-11-03 2011-05-12 Husky Injection Molding Systems Ltd. A method and system for operating an injection molding machine
EP2826615A1 (de) 2009-11-03 2015-01-21 Husky Injection Molding Systems S.A. Verfahren und System zum Betreiben einer Injektionsformungsmaschine
EP2826616A1 (de) 2009-11-03 2015-01-21 Husky Injection Molding Systems S.A. Verfahren und System zum Betreiben einer Injektionsformungsmaschine
FR2969526A1 (fr) * 2010-12-22 2012-06-29 Visteon Global Tech Inc Procede et dispositif pour le controle de l'ouverture partielle d'un moule d'injection de matiere plastique
EP3131729B1 (de) 2014-04-15 2018-11-28 Plastisud Tandemwerkzeug zum herstellen spritzgegossener kunststoffteile
US10857712B2 (en) 2014-04-15 2020-12-08 Plastisud Tandem mold for creating injection-molded parts from synthetic material
CN105114367A (zh) * 2015-09-02 2015-12-02 上海核工程研究设计院 一种用于核电站抽真空系统的具有可调式喷嘴的真空喷射器

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KR910007645A (ko) 1991-05-30
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EP0425060B1 (de) 1995-08-23
DE69021824T2 (de) 1996-04-18
EP0425060A3 (en) 1992-01-29

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